1. Field of the Invention
The invention relates to a method of wrapping a spool with metallic ribbon, as well as to the spool and to the ribbon designed to carry out said method, and to the spool so wrapped.
2. Description of the Prior Art
To store and handle wires, cables, and sheets, these products are normally packed on spools, usually referred to as "reels", composed of a hub and two flanges. Such spools are provided with a wrapping or cover to protect them against blows and attack by foreign substances.
In previously known structures, this wrapping or cover consisted of a number of crosspieces of wood disposed parallel to the axis of the spool, with the ends of the pieces resting on the two flanges of the spool and being nailed on the periphery thereof. However, protection of the wound spools in this manner was time-consuming and costly.
To facilitate the installation of these crosspieces, these crosspieces may be preassembled to form a curtain which then need only be unwound and wrapped around the spool, with the two ends thereof being connected together by applying a tension between them to ensure that the wrapping is held fast. (French Pat. No. 2,095,890).
These crosspieces, generally referred to as "staves" by analogy with the longitudinal pieces of wood forming the body of barrels, which rest on the periphery of the flanges of the spool have the drawback of increasing very considerably the space taken up by the spools which, needless to say, increases the cost of transport and storage. In addition to this considerable increase in the space taken up by the spools, these crosspieces have also proven to be fragile to impacts.
To obtain a more resistant wrapping, it is also well known (U.S. Pat. No. 1,913,477) to substitute for the crosspieces of wood, crosspieces of metal or protecting plates that have previously been flanged so that thereafter they can assume without stress the shape of the periphery of the flanges on which they will be fixed.
The crosspieces distributed on the periphery of the spools, be they of wood or of metal, include gaps between them that enable foreign substances to gain access to the product packed on the spool. Further, these crosspieces from flat surfaces on the periphery of the spool that interfere with the rolling of the spools on the ground. Further, when handling of these spools, engagement of the lift straps under the spool is difficult because, at least in the case of the crosspieces of wood, the spool rests on the ground along an entire generating line.
To overcome some of the drawbacks resulting from the use of wood staves or metal protecting plates, it is common practice (French Pat. No. 2,324,140) to wrap the product packed on the spool with a ribbon whose width is slightly less than the distance between the flanges. Such a ribbon no longer rests on the periphery of the flanges, but rather on the wound product itself, that is to say, usually after the interposition of blocks of plastic foam.
If the ribbon does not increase the space taken up by the spools, the ribbon does not interfere with the winding operation and enables the lift straps to pass. However, unlike the staves of wood which assures the clamping of the flanges together, the ribbon no longer strengthens the spools. Moreover, despite the plastic-foam blocks that may be interposed, impacts on the ribbon are quickly transmitted to the product.
The major drawbacks, however, remain in the necessity either of splitting the ribbon in order to adapt it to the actual width of each spool, whose factory tolerances are rather substantial, or making the ribbon considerably less wide than the average distance between the flanges in order to allow for factory tolerances. In such arrangements the product may be undesirably uncovered near the flanges.
Where the thickness of the ribbon does not excessively increase the diametrical space occupied by the spools, it is well known (French Pat. No. 2,251,481) to use a ribbon with a width greater than the distance measured between the external surfaces of the flanges in order to obtain a better covering over of the product, so that, in the manner of staves, the edges of this ribbon rest on the periphery of the flanges of the spool while its median portion is situated in the same plane as said edges and surrounds the product. For its immobilization in axial translation, the surplus marginal strips of the ribbon are then simply bent down against the edge of the external surfaces of the flanges.
To prevent them from producing stresses in the median portion of the ribbon and to facilitate the bendingdown operation prior to said operation, the marginal strips are subjected to an undulation process.
If the ribbon does not increase materially the space taken up by the spool, since it is fixed simply by bending down the marginal strips, it is nevertheless insufficiently anchored to strengthen the spool. Also, for that matter, it fails to prevent the marginal strips from slipping in the event of an impact on its median portion, so that the slightest deformation places said marginal strips in a position which causes them to disengage.
In addition, as in the case of staves of wood or metal protection plates, the spool rests on the ground along an entire generating line so that, in order to lift it, the straps cannot simply be slipped under the spool. To free a passage for the straps and especially to achieve a relative strengthening of the spool, it is also well known (U.S. Pat. No. 2,642,990) to provide the periphery of the spool with a ribbon that has previously and permanently be profiled not only transversely so that, with respect to its median portion which extends to the vicinity of the internal surfaces of the flanges, its edges are raised in order to create grooves that cover the periphery of said flanges, but also longitudinally in accordance with the curves of the flanges so as to avoid any stress in the ribbon during and after its installation. Short of providing thick and, hence, heavy and costly, ribbons, the ribbon of a spool wrapped according to this method still tolerates the slightest shock caused by the deformations of its median portion.
It is also common practice (U.S. Pat. No. 2,642,990) to flange transverse ribs in this ribbon not only to guarantee its longitudinal profiling without stresses, but especially to strengthen it transversely. Unfortunately, however, this also increases the cost price and interferes with the passage of the lift straps.